feat: use program change instead of control change for sketch switch (#8

)

src/constants.ts

@@ -1,5 +1,3 @@
 export const configFileName = "8tlr-router.config.yaml";
 
-export const sketchSwitchControlChangeNumber = 119;
-
 export const frontendUpdateInterval = 100;

src/frontend/updateSketch.ts

@@ -1,7 +1,7 @@
 export function updateSketch(uiUpdate: UiUpdate) {
   const { type, track, sketch } = uiUpdate;
 
-  if (type !== "sketch") {
+  if (type !== "pgm") {
     return;
   }
 

src/global.d.ts

@@ -4,7 +4,7 @@ declare const MAIN_WINDOW_VITE_DEV_SERVER_URL: string;
 declare const MAIN_WINDOW_VITE_NAME: string;
 
 type TrackName = "fhyd" | "tang" | "duri" | "poml" | "tiff" | "coco" | "plum" | "flam";
-type MidiMessageType = "note-on" | "note-off" | "cc" | "at" | "pb" | "sketch";
+type MidiMessageType = "note-on" | "note-off" | "cc" | "at" | "pb" | "pgm";
 type Sketch = 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8;
 
 interface UiUpdate {

src/midi/createMidiMessageRouter.test.ts

@@ -1,6 +1,5 @@
 import type { MidiMessage, Output } from "@julusian/midi";
 import { createMidiMessageRouter, loggers } from "./createMidiMessageRouter";
-import { sketchSwitchControlChangeNumber } from "../constants";
 
 const outputs: Output[] = new Array(4).fill(null).map(() => ({
   sendMessage: vi.fn(),
@@ -17,8 +16,8 @@ const outputs: Output[] = new Array(4).fill(null).map(() => ({
 
 const NOTE_ON_CH1_C2_V100: MidiMessage = [0x90, 0x30, 0x64];
 const NOTE_ON_CH9_C2_V100: MidiMessage = [0x98, 0x30, 0x64];
-const SKETCH_SWITCH_2: MidiMessage = [0xb0, sketchSwitchControlChangeNumber, 0x10];
-const SKETCH_SWITCH_3: MidiMessage = [0xb0, sketchSwitchControlChangeNumber, 0x20];
+const PROGRAM_CHANGE_2: MidiMessage = [0xc0, 0x01];
+const PROGRAM_CHANGE_3: MidiMessage = [0xc0, 0x02];
 
 vi.mock("debug", () => ({ default: () => vi.fn() }));
 
@@ -30,7 +29,7 @@ describe("The router function created by createMidiMessageRouter", () => {
     midiMessageRouter = createMidiMessageRouter({ outputs });
   });
 
-  describe("when no sketch switch MIDI message has been received previously", () => {
+  describe("when no program change MIDI message has been received previously", () => {
     describe("and it receives a MIDI message", () => {
       beforeEach(() => {
         result = midiMessageRouter(0, NOTE_ON_CH1_C2_V100);
@@ -73,21 +72,20 @@ describe("The router function created by createMidiMessageRouter", () => {
     });
   });
 
-  describe("when it receives a sketch switch control change for sketch 2", () => {
+  describe("when it receives a program change for sketch 2", () => {
     beforeEach(() => {
-      result = midiMessageRouter(0, SKETCH_SWITCH_2);
+      result = midiMessageRouter(0, PROGRAM_CHANGE_2);
     });
-    it(`Logs a debug message that indicates that MIDI messages arriving on channel 1
-         will now be routed to channel 9 on the same output port`, () => {
-      expect(loggers.sketch).toHaveBeenCalledWith("  [SK]  ch:  1 | skt:     2 | val:    16");
+    it(`Logs a debug message that indicates that a program change message
+         with value 1 was received (pgm is zero-based, so 1 is sketch 2)`, () => {
+      expect(loggers.pgm).toHaveBeenCalledWith("     [PG]  ch:  1 |            | val:     1");
     });
     it("returns the correct result", () => {
       expect(result).toMatchInlineSnapshot(`
         {
           "outputMidiMessage": [
-            184,
-            119,
-            16,
+            200,
+            1,
           ],
           "outputPortIndex": 0,
         }
@@ -121,19 +119,18 @@ describe("The router function created by createMidiMessageRouter", () => {
 
   describe("when it receives a sketch switch control change for sketch 3", () => {
     beforeEach(() => {
-      result = midiMessageRouter(0, SKETCH_SWITCH_3);
+      result = midiMessageRouter(0, PROGRAM_CHANGE_3);
     });
-    it(`Logs a debug message that indicates that MIDI messages arriving on channel 1
-         will now be routed to channel 1 on output port 2`, () => {
-      expect(loggers.sketch).toHaveBeenCalledWith("  [SK]  ch:  1 | skt:     3 | val:    32");
+    it(`Logs a debug message that indicates that a program change message
+         with value 1 was received (pgm is zero-based, so 2 is sketch 3)`, () => {
+      expect(loggers.pgm).toHaveBeenCalledWith("     [PG]  ch:  1 |            | val:     2");
     });
     it("returns the correct result", () => {
       expect(result).toMatchInlineSnapshot(`
         {
           "outputMidiMessage": [
-            176,
-            119,
-            32,
+            192,
+            2,
           ],
           "outputPortIndex": 1,
         }

src/midi/createMidiMessageRouter.ts

@@ -1,9 +1,8 @@
 import type { MidiMessage, Output } from "@julusian/midi";
 import { getMidiChannel } from "./getMidiChannel";
 import createDebug from "debug";
-import { isSketchSwitch } from "./isSketchSwitch";
+import { isProgramChange } from "./isProgramChange";
 import { formatMidiMessage } from "../utils";
-import { getSketchIndex } from "./getSketchIndex";
 import { getMidiMessageType } from "./getMidiMessageType";
 
 export const loggers = {
@@ -12,7 +11,7 @@ export const loggers = {
   cc: createDebug("8tlr-router:midi:router:cc"),
   at: createDebug("8tlr-router:midi:router:at"),
   pb: createDebug("8tlr-router:midi:router:pb"),
-  sketch: createDebug("8tlr-router:midi:router:sketch"),
+  pgm: createDebug("8tlr-router:midi:router:pgm"),
   other: createDebug("8tlr-router:midi:router:other"),
 };
 
@@ -22,7 +21,7 @@ const leftPaddings = {
   cc: 6,
   at: 6,
   pb: 6,
-  sketch: 2,
+  pgm: 5,
   other: 3,
 };
 
@@ -42,17 +41,39 @@ export function createMidiMessageRouter({ outputs }: Args): MidiMessageRouter {
       return null;
     }
 
-    const isSketchSwitchMessage = isSketchSwitch(inputMidiMessage);
-    if (isSketchSwitchMessage) {
-      const sketchIndex = getSketchIndex(inputMidiMessage);
+    const isProgramChangeMessage = isProgramChange(inputMidiMessage);
+    if (isProgramChangeMessage) {
+      const sketchIndex = inputMidiMessage[1];
+
+      /*
+       * 0 => 0
+       * 1 => 0
+       * 2 => 1
+       * 3 => 1
+       * 4 => 2
+       * 5 => 2
+       * 6 => 3
+       * 7 => 3
+       */
       selectedOutputIndices[inputChannel] = Math.floor(sketchIndex / 2);
+
+      /*
+       * 0 => false
+       * 1 => true
+       * 2 => false
+       * 3 => true
+       * 4 => false
+       * 5 => true
+       * 6 => false
+       * 7 => true
+       */
       shiftChannel[inputChannel] = sketchIndex % 2 !== 0;
     }
     if (shiftChannel[inputChannel]) {
       outputMidiMessage[0] += 8;
     }
     const outputPortIndex = selectedOutputIndices[inputChannel];
-    if (!isSketchSwitchMessage) {
+    if (!isProgramChangeMessage) {
       const midiMessageType = getMidiMessageType(inputMidiMessage);
       const logger = midiMessageType === null ? loggers.other : loggers[midiMessageType];
       const leftPadding = midiMessageType === null ? leftPaddings.other : leftPaddings[midiMessageType];
@@ -61,7 +82,7 @@ export function createMidiMessageRouter({ outputs }: Args): MidiMessageRouter {
         `${" ".repeat(leftPadding)}${formatMidiMessage(inputMidiMessage, "pretty")} >>> ${formatMidiMessage(outputMidiMessage, "pretty")} | port: ${outputPortIndex + 1}`,
       );
     } else {
-      loggers.sketch(`  ${formatMidiMessage(inputMidiMessage, "pretty")}`);
+      loggers.pgm(`     ${formatMidiMessage(inputMidiMessage, "pretty")}`);
     }
 
     return {

src/midi/getMidiMessageType.ts

@@ -1,30 +1,30 @@
 import type { MidiMessage } from "@julusian/midi";
 
-import { isSketchSwitch } from "./isSketchSwitch";
-import { isNoteOn } from "./isNoteOn";
-import { isNoteOff } from "./isNoteOff";
-import { isControlChange } from "./isControlChange";
 import { isAfterTouch } from "./isAfterTouch";
+import { isControlChange } from "./isControlChange";
+import { isNoteOff } from "./isNoteOff";
+import { isNoteOn } from "./isNoteOn";
 import { isPitchBend } from "./isPitchBend";
+import { isProgramChange } from "./isProgramChange";
 
 export function getMidiMessageType(midiMessage: MidiMessage): MidiMessageType | null {
-  if (isSketchSwitch(midiMessage)) {
-    return "sketch";
+  if (isAfterTouch(midiMessage)) {
+    return "at";
   }
-  if (isNoteOn(midiMessage)) {
-    return "note-on";
+  if (isControlChange(midiMessage)) {
+    return "cc";
   }
   if (isNoteOff(midiMessage)) {
     return "note-off";
   }
-  if (isControlChange(midiMessage)) {
-    return "cc";
-  }
-  if (isAfterTouch(midiMessage)) {
-    return "at";
+  if (isNoteOn(midiMessage)) {
+    return "note-on";
   }
   if (isPitchBend(midiMessage)) {
-    return "sketch";
+    return "pb";
+  }
+  if (isProgramChange(midiMessage)) {
+    return "pgm";
   }
   return null;
 }

src/midi/getMidiMessageTypeName.ts

@@ -1,30 +1,30 @@
 import type { MidiMessage } from "@julusian/midi";
 
-import { isSketchSwitch } from "./isSketchSwitch";
-import { isNoteOn } from "./isNoteOn";
-import { isNoteOff } from "./isNoteOff";
-import { isControlChange } from "./isControlChange";
 import { isAfterTouch } from "./isAfterTouch";
+import { isControlChange } from "./isControlChange";
+import { isNoteOff } from "./isNoteOff";
+import { isNoteOn } from "./isNoteOn";
 import { isPitchBend } from "./isPitchBend";
+import { isProgramChange } from "./isProgramChange";
 
 export function getMidiMessageTypeName(midiMessage: MidiMessage, verbose = false) {
-  if (isSketchSwitch(midiMessage)) {
-    return verbose ? "sketch switch" : "SK";
+  if (isAfterTouch(midiMessage)) {
+    return verbose ? "aftertouch" : "AT";
   }
-  if (isNoteOn(midiMessage)) {
-    return verbose ? "note on" : "NO";
+  if (isControlChange(midiMessage)) {
+    return verbose ? "control change" : "CC";
   }
   if (isNoteOff(midiMessage)) {
     return verbose ? "note off" : "NF";
   }
-  if (isControlChange(midiMessage)) {
-    return verbose ? "control change" : "CC";
-  }
-  if (isAfterTouch(midiMessage)) {
-    return verbose ? "aftertouch" : "AT";
+  if (isNoteOn(midiMessage)) {
+    return verbose ? "note on" : "NO";
   }
   if (isPitchBend(midiMessage)) {
     return verbose ? "pitch bend" : "PB";
   }
+  if (isProgramChange(midiMessage)) {
+    return verbose ? "program change" : "PG";
+  }
   return null;
 }

src/midi/index.ts

@@ -2,16 +2,15 @@ export { createExitHandler } from "./createExitHandler";
 export { createMidiMessageHandler } from "./createMidiMessageHandler";
 export { createMidiMessageRouter } from "./createMidiMessageRouter";
 export { getMidiChannel } from "./getMidiChannel";
-export { getPortIndex } from "./getPortIndex";
-export { getSketchIndex } from "./getSketchIndex";
 export { getMidiMessageType } from "./getMidiMessageType";
 export { getMidiMessageTypeName } from "./getMidiMessageTypeName";
+export { getPitchBendValue } from "./getPitchBendValue";
+export { getPortIndex } from "./getPortIndex";
 export { initPort } from "./initPort";
-export { isControlChange } from "./isControlChange";
-export { isSketchSwitch } from "./isSketchSwitch";
-export { sendAllNotesOff } from "./sendAllNotesOff";
 export { isAfterTouch } from "./isAfterTouch";
-export { isNoteOn } from "./isNoteOn";
+export { isControlChange } from "./isControlChange";
 export { isNoteOff } from "./isNoteOff";
+export { isNoteOn } from "./isNoteOn";
 export { isPitchBend } from "./isPitchBend";
-export { getPitchBendValue } from "./getPitchBendValue";
+export { isProgramChange } from "./isProgramChange";
+export { sendAllNotesOff } from "./sendAllNotesOff";

src/midi/isControlChange.test.ts

@@ -4,7 +4,7 @@ describe("The isControlChange function", () => {
   describe.each`
     midiMessage           | value
     ${[0xb0, 0x01, 0x64]} | ${true}
-    ${[0xb4, 0x77, 0x24]} | ${false}
+    ${[0xb4, 0x77, 0x24]} | ${true}
     ${[0x90, 0x3c, 0x40]} | ${false}
   `("when it receives MIDI message $midiMessage", ({ midiMessage, value }) => {
     it(`returns ${value}`, () => {

src/midi/isControlChange.ts

@@ -1,7 +1,6 @@
 import type { MidiMessage } from "@julusian/midi";
-import { sketchSwitchControlChangeNumber } from "../constants";
 
 export function isControlChange(message: MidiMessage) {
-  const [statusByte, controlNumber] = message;
-  return (statusByte & 0xf0) === 0xb0 && controlNumber !== sketchSwitchControlChangeNumber;
+  const [statusByte] = message;
+  return (statusByte & 0xf0) === 0xb0;
 }

src/midi/isProgramChange.ts

@@ -0,0 +1,6 @@
+import type { MidiMessage } from "@julusian/midi";
+
+export function isProgramChange(message: MidiMessage) {
+  const [statusByte] = message;
+  return (statusByte & 0xf0) === 0xc0;
+}

src/ui/createUiUpdater.ts

@@ -1,12 +1,12 @@
 import type { BrowserWindow } from "electron";
 import type { MidiMessage } from "@julusian/midi";
 import { getTrackName } from "./getTrackName";
-import { getType } from "./getType";
+import { getMidiMessageType } from "../midi";
 import { getSketch } from "./getSketch";
 
 export function createUiUpdater(browserWindow: BrowserWindow) {
   return (midiMessage: MidiMessage, portIndex: number) => {
-    const type = getType(midiMessage);
+    const type = getMidiMessageType(midiMessage);
     if (!type) {
       // we only update the UI for note, control change, aftertouch (poly and channel),
       // pitch bend and sketch change MIDI messages, everything else is irrelevant